When patinated steels (Atmofix, Corten) began to be used more and more in the manufacture of high-voltage transmission masts, a maximum corrosion resistance period of 30 years was set by experts on corrosion issues. This time period is now over and the high-voltage transmission systems are already severely damaged by corrosion, which reduces the design load capacity and static properties of the structures and this problem needs to be addressed. CREPEX® can be used to treat existing transmission systems without interrupting the power supply.
Comparison of the cost of treating a high-voltage transmission pole with CREPEX® coating and hot-dip galvanizing (not including the application of a topcoat of the customer’s choice).
The subject of the treatment was an already corroded high-voltage transmission tower weighing 20 tonnes and with a surface area of 550 m2:
| Options | Hot dip galvanizing | CREPEX |
| Treatment of surfaces damaged by corrosion | No | Yes |
| Treatment of surfaces over 6 meters | No | Yes |
| Welding of already treated surfaces | No | Yes |
| Welding machine | No | Yes |
Other related costs | Hot dip galvanizing | CREPEX |
Pole dismantling, diversion of lines, interruption of power supply | Yes | No |
Transport of material to the zinc plant | Yes | No |
Necessary surface preparation before galvanizing | Yes | No |
Transportation back to the site, assembly and installation | Yes | No |
Reverse installation of high voltage line wires | Yes | No |
Follow-up surface treatment after 2 years | Yes | No |
Treating columns with CREPEX® coating eliminates all the costs and complications listed in the table above and only the cost of the coating application needs to be added to the purchase price of the coating.
To the cost of the hot-dip galvanizing treatment, the large-scale losses from power interruptions, etc. must be added.
The direct costs of hot-dip galvanizing the profiles are calculated at a rate per 1 kg of the weight of the profile to be galvanized or per 1 m2 of galvanizing. The achievable price for the weight galvanising option is in the range of CZK 20-30 per 1 kg, which for a given column weighing 20 tonnes at an average price amounts to approximately CZK 500 000, and the estimated cost of dismantling, transport and preparation, removal to site and assembly amounts to approximately CZK 500 000, making a total cost of CZK 1 000 000. Alternatively, the galvanising option, calculated according to the area, at around CZK 750 per 1 m2, amounts to CZK 412 500 for a given column with an area of 550 m2 and an estimated cost of dismantling, transport and preparation, removal to the site and assembly of approximately CZK 500 000, which in total amounts to a cost of CZK 912 500.
Painting or spraying equipment is now available to everyone and is usually available to all companies that carry out at least basic maintenance.
The cost of treating profiles with CREPEX® can be around 500 CZK / 1 l for larger orders. To make the calculation easier, let’s calculate the average consumption of the coating, i.e. 1 l of coating per 10 m2.
The resulting direct cost of procuring the CREPEX® coating for the column in question is 27,500 CZK and the estimated cost of spraying or painting can range from 20,000 – 50,000 CZK, which together makes the final cost less than 100,000 CZK.
The cost of painting or spraying the CREPEX® coating is therefore hundreds of thousands of Czech crowns less than the cost of hot-dip galvanizing. The difference in the cost of treating a single pole of a high-voltage transmission system can therefore amount to CZK 900 000, without quantifying the loss of power supply interruption for the entire period of hot-dip galvanising repair.
In contrast, the treatment of the application with a CREPEX® coating system can amount to CZK 100 000. This amount must be increased by the cost of the topcoat, chosen according to the client’s requirements.
CREPEX® application protection is faster, less complicated, cheaper and, last but not least, more effective and environmentally friendly.